The present invention concerns a door driving-mechanism torque transmission for transmitting torque from a door driving motor assembly, especially a geared motor, to a shaft connected to a door panel. A torque transmission, a door-driving mechanism, and a door of these genera are known from WO 94/00665, which will be discussed in detail hereinafter.
A door panel with a door-driving motor assembly is known from EP 0 405 059 A1. Interposed between its output shaft and a door drive-mechanism torque transmission in the form of a door shaft that secures and/or actuates the panel are a tractioning-means transmission with a driving component in the form of a transmission input shaft and a driven component in the form of a transmission output shaft. Both components are accommodated in an accommodation constituted by a transmission housing. The housing comprises two identical halves fastened rigidly together and accommodating the tractioning-means transmission. The transmission housing and hence the overall transmission on the whole rotate perpendicular as a whole to the parallel axes of rotation of the transmission shafts, the transmission-input shaft and the transmission output shaft, that is, around the axis of the door shaft and can be pivoted subject to reaction forces exerted by the panel being actuated against a shock absorption component and/or a resilient component in the form of a spring. The door-driving motor assembly rests on the transmission input shaft and is accordingly connected to the housing. The initial motion of the door-driving motor assembly generates an impact-like force (torque impact) that is on the whole resiliently accommodated by the pivoting motion of the known door driving-mechanism torque transmission against the resilient component. This pivoting motion is also exploited for an overload disengagement mechanism.
With the prior art disclosed in European Patent 0 405 059 A1 as its point of departure, the aforesaid WO 94/00665 proposes an improvement in the form of a door driving-mechanism torque transmission.
This known transmission is, like the one disclosed in WO 94/00665, a tractioning-means transmission and part of a mechanism for driving a door panel. The panel is provided with a door shaft coupled to it. The output shaft of a door-driving motor assembly accommodated in a driving-mechanism housing is connected to the door shaft by way of the tractioning-means transmission, which is accommodated in a transmission housing. The known door driving-mechanism torque transmission has a driving component in the form of an input shaft connected to the door-driving motor assembly""s output shaft and a driven component in the form of an output shaft connected to the door shaft. The axes of rotation of the input and output shafts are separated by a multiple of the radii of gear wheels mounted on the shafts and coupled together by the tractioning means. The driving-mechanism housing of the door driving motor assembly is fixed in position and rotates along with the transmission housing and hence with the door driving-mechanism torque transmission on the whole in such a way that any torque between the door shaft and the door driving motor assembly""s output shaft is accommodated as if by a rigid lever.
The object of the present invention is accordingly to improve a door driving-mechanism torque transmission with respect to smooth operation, length of life, and frequency of repair.
Instead of a rigid torque-transmission housing that transmits torque like a single-arm lever accordingly, the present invention exploits a bearing assembly with two separate halves, one for the door driving-mechanism torque transmission""s driving component and one for its driven component. Since these halves are connected together not rigidly but elastically, they will attenuate any impacts or vibrations in the torque they transmit between the driving component and the driven component. Both components are accordingly elastically connected such that they can move toward or apart from each other and especially pivot in relation to each other at least slightly (a few millimeters, 0.5-5 mm for example) preferably within the plane occupied by at least one.
The torsional impacts exerted on the door-driving motor assembly and its fixtures in the torque transmission in the form of a rigid lever considered especially preferred in WO 94/00665 are admittedly attenuated by being transmitted over a long lever. The impacts, however, must be accommodated by the torque-transmission train as a whole, and this has resulted in breakage of the weakest components therein, like the shaft coupling between the door driving-mechanism torque transmission and the door shaft for instance, which must then be replaced. The door driving-mechanism torque transmission in accordance with the present invention will also run more smoothly than the known transmission, not only when started and with the torsion impact to be expected at that instant but also while the door panel is in motion. The door shafts available in practice, that is, almost never rotate trues, not only because they naturally exhibit considerable imbalance due to the engagement of the torsion spring, the overhead door armor, or similar structures but also because the forces exerted on them vary constantly as the shaft turns. Furthermore, the door shafts available in practice are also absolutely more powerfully inflected. All of these problems result in more or less powerful vibrations both circumferentially and axially, which are accommodated in accordance with the present invention by relatively small unresilient masses (only the driven-component bearing being exposed more or less unresiliently to impacts deriving from the door shaft), and these are in any case transmitted attenuated to the driving-component bearing half and hence to the door-driving motor assembly by way of the elastic attachment.
When torsion impacts occur, accordingly, it is not the door driving mechanism as a whole, comprising, that is, the door driving motor assembly and the door driving-mechanism torque transmission, that yields elastically as at the prior art represented by EP 0 405 059 A1, but only the bearing halves, toward each other, avoiding the drawbacks encountered in the door driving-mechanism torque transmission disclosed in that patent, which are in particular expressed in the difficulties associated with its manufacture and installation. The number of masses that accompany such torsion impacts without being resiliently supported is also much lower in accordance with the present invention than at the aforesaid state of the art, which not only contributes to smooth operation but also helps to prevent damage deriving from impacts against the door driving motor assembly. The present invention accordingly combines all the advantages of the known door driving mechanism torque transmission while lacking its drawbacks.
In one advantageous embodiment of the present invention, both bearing halves can be elastically connected together at any desired distance apart. The door driving-mechanism torque transmission can accordingly be adapted to span various distances between the door-driving motor assembly and the door shaft. This feature increases the range of possibilities for installing the assembly.
When both bearing halves are elastically connected such that they can move straight or at an angle toward and away from each other at least within a plane perpendicular to at least one of the two axes of rotation, especially the axis of the driven component, torsional vibrations around that axis can be attenuated by a relative elastic pivoting motion. A connection that permits such relative angular motions can be established in various ways. The bearing halves can for instance be connected by a pivot or by a joint (even a ball joint), the pivoting motion occurring against some sort of elastic component, a compression or tension spring for example, or a rubber block, a rotating rod, or a torsion spring. When the bearing halves are elastically connected at at least two separated points of attachment, not only motions around one axis, but also translational motions on the part of the bearing halves toward and away from each other can be attenuated by the elastic connection at the points of attachment even though the attachment is sufficiently fixed at the two points to actually transmit the requisite torque. Thus, even impacts and vibrations that occur radially with respect to an axis of rotation due to wobbling of the door shaft can be attenuated.
Several separated points of attachment can be established by means of an elongated elastic component, a rubber strip for example, by way of which the bearing halves can engage surface to surface or linearly. It is, however, preferable for the points of attachment to comprise separated connecting blocks or liners of an elastic material, by way of which the two bearing halves are connected.
One of the bearing halves can in this event be provided with pins that engage a connection bushing in the form of a rubber bushing and the other with fixtures, cylindrical for example, that surround or enclose the rubber bushings. The rigidity and attenuating characteristics can, directionally as well, be varied as desired by varying the positions, directions, and material of the connection bushings (by varying the Shore hardness and/or width of the rubber bushings), relatively as well. One advantageous embodiment of the present invention accordingly, is characterized by an assortment of elastic components for connecting the two bearing halves together and having different elastic properties, especially deriving from different hardnesses and/or from such various dimensions as outside diameter, and allowing specific adjustment of rigidity and/or torsional-vibration attenuation characteristics in accordance with which particular components are selected from the assortment.
The bearing halves can be of any form appropriate for accommodating the components and for connecting them such that torsion impacts and other impacts and vibrations in the driving train can be absorbed. They can for example comprise flat stamped-out shapes or lengths of structural section etc. with a component-bearing area and a connecting area, with the coupling between the components covered by an additional protective enclosure, which can be in several parts for example and which can be of plastic for example. Such an additional enclosure, however, will be unnecessary when both bearing halves are elastically coupled, and especially mutually telescopically engaging such as to allow relative angular motion with play, individual components of a torque transmission housing, preferably such that each essentially comprises two especially identical and mutually connected housing shells.
The coupling itself can be of various forms. A cogwheel coupling or universal joint would be possible for example. The maximal degree of freedom with respect to the distance to be spanned and to how the bearing halves move in relation to attenuation, however, is provided, as at the aforesaid state of the art, in an embodiment wherein the coupling is in the form of at least one continuous tractioning means, a chain, cogged band, or belt for example, whereby each half is provided with a wheel that engages the at least one means mechanically or frictionally.
In this event it will be preferable for a tractioning-means transmission comprising the at least one tractioning means and both wheels is enclosed in the shells that comprise the torque-transmission housing whereby in particular tensioning means draw the two strands of the tractioning means together inside the transmission housing.
In one advantageous embodiment of the door-driving mechanism in accordance with the present invention, the driving component bearing half is fastened to a stationary driving mechanism housing for the door-driving motor assembly, especially extending in any desired direction, whereby, however, the driving-component bearing half is elastically disengaged from the driving-mechanism housing due to the elastic connection between the two bearing halves for the purpose of attenuating torsional vibrations. It is accordingly only the driven-component bearing that vibrates in tune with torsional or radial vibrations in the door shaft. The driving-component bearing half is uncoupled therefrom and fastened stationary due to the connection with the stationary driving-mechanism housing. This arrangement decreases noise and prevents damage from impacts.
It would in principle alternatively be conceivable to cushion the bearing-halves connection with a viscous fluid or with gas in addition to or instead of an elastic solid. In addition to an elastic connecting component, a friction component that would provide frictional attenuation and/or a liquid shock absorber could be inserted between the bearing halves to attenuate vibrations. In principle, the two bearing halves or the two components of the door driving-mechanism torque transmission or even both could be connected by any devices known for example from the field of torsional vibration shock absorbers employed in motor-vehicle couplings or motor-vehicle running gear, specifically dashpots, proportional shock absorbers, etc.
The present invention especially relates to a door driving mechanism torque transmission of the genus known from WO 94/00665. Reference is specifically directed to that publication; and to EP 0 405 059 A1 for any details of the invention not explained herein.
Instead of a transmission housing in the form of a rigid lever fastened to the driving-mechanism housing, the door driving-mechanism torque transmission in accordance with the present invention features driving and driven components that are preferably both circumferentially and radially and even possibly axially uncoupled from the door shaft and only elastically connected, especially in the form of transmission or chain wheels. The present invention accordingly comprises elastic uncoupling of the driving component of a torque transmission from its driven component to the extent that torque is transmitted from an input shaft to an output shaft precisely not in the manner of a rigid lever but elastically attenuated. It is for this purpose that an elastic connection is provided between the bearings accommodating the driving and the driven components that also allows to a certain extent angular motion within a plane perpendicular to the driving and driven axes.
The advantages of the elastic torque-transmission component in accordance with the present invention over the conventional torque-transmission disclosed in WO 94/00665 are to be found in the gentle treatment of the door and of the driving-motor assembly resulting from the absorption of impacts and in the smooth operation of the door.